Mechanism for producing pivotal movement of an arm



Feb. 20, 1968 s. M. SLAWSKY 3,369,415

MECHANISM FOR PRODUCING PIVOTAL MOVEMENT OF AN ARM Filed July 1, 1965 4 Sheets-Sheet 1 'SGIGZ I42 FIG 2 INVENTOR STANLEY M. SLAWSKY WMVM ATTORNEYS Feb. 20, 1968 s. M. SLAWSKY 3,369,415

MECHANISM FOR PRODUCING PIVOTAL MOVEMENT OF AN ARM Filed July 1, 1965 4 Sheets-Sheet 2 F IG. 4. INVENTOR STANLEY M. SLAWSKY M MVM ATTORNEYS Feb. 20, 1968 s. M. SLAWSKY MECHANISM FOR FRODUCING PIVOTAL MOVEMENT OF AN ARM Filed July 1, 1965 4 Sheets-Sheet 5 INVENfOR STANLEY M. SLAWSKY FIG.5.

ATTOR NEYS Feb. 20, 1968 s. M. SLAWSKY 3,359,415

MECHANISM FOR FRODUCING PIVOTALI MOVEMENT OF AN ARM Filed July 1, 1965 4 Sheets-Sheet 4 I88} 204 gms 206 I :90 I94 I96 A r 192 2l0 202 201a F FIG. 7 A 2l8 |98 2m 1 200 I68 I80 20: I72 L ATTORNEYS Filed July 1, 1965, Ser. No. 468,702 8 Claims. (Cl. 74-8922) ABSTRACT OF THE DISCLOSURE An arm is mounted by means spaced inwardly from the outer end of the arm to provide for pivotal movement of the arm about a point on the arm intermediate the mounting means and the outer end of the arm and is provided with means to oscillate the arm about said point This invention relates to a mechanism for producing pivotal movement of an arm. More particularly, it relates to such a mechanism wherein the arm pivots about a point substantially at the outer end thereof and is mounted for movement by means spaced inwardly from the outer end of the arm,

It is frequently desired to oscillate or rock an arm about a point located at the outer end of the arm while still having the outer end of the arm free from any mounting mechanism. A typical application is an ultrasonic transducer scanning arm which is to be applied against the patients skins If the center of rotation of the trans" ducer arm is other than at a point adjacent the patients skin and the outer face of the transducer, the transducer has an objectionable sliding action relative to the patients skin. Since an ultrasonic transducer scanning arm application is a typical one, it will be used hereinafter in describing the invention and it will be understood that the invention is not limited to such an application:

In accordance with this invention, there is provided means spaced inwardly from the outer end of the trans ducer arm mounting the arm for pivotal movement about a point at or substantially at. the outer face of the transducer The invention will be fully understood from a reading of the following description in conjunction with the draw ings in which:

FIGURE 1 is a invention;

FIGURE 2 is a front elevation of the apparatus o FIGURE 1;

FIGURE 3 is a rear FIGURE 1;

FIGURE 4 is a simplified horizontal section of a portion of the apparatus illustrating various positions assumed by the transducer arm;

FIGURE 5 is a horizontal section partially broken away taken on the plane indicated by the line 5-5 in. FIG- URE 2;

FIGURE 6 is a horizontal section taken the plane indicated by the line 6-6 in FIGURE 2;

FIGURE 7 is a wiring diagram of a circuit for reversing the motor of the apparatus in FIGURE 1,:

plan view of apparatus embodying the elevation of the apparatus of 3,3 6 9,4 i 5- Patented 1? ch.) 20, i 968 inc FIGURE 8 is a view taken. on the plane indicated by the line 8-8 in FIGURE 6;

FIGURE 9 is a view taken on the plane indicated by the line 9-9 in FIGURE 3; and

FIGURE 10 is a diagrammatic view illustrating an alternative embodiment of the inventionc Referring first to FIGURE 1, an ultrasonic scanning apparatus 2 has a frame 4 provided. with transverse plates 6 and 8. A. two-phase AC motor is mounted on plate 8 and is provided with a reduction gear section 14 -which drives an output shaft 16. A bevel gear 118 secured to shaft 16 drives bevel gear 20 secured to shaft 22: Shaft 22 is mounted for rotation between plates 6 and 8 and has secured thereto a gear 24 which drives a gear 26 secured to shaft 28 which is mounted for rotation between plates 6 and 8,

Shaft 28 has secured thereto a cam member 30 (FIG URE 6) which is adapted to engage roller 32 on arm 34 of limit switch 36 and roller 38 on arm 40 of limit switch 42 A drum 50 is fixedly secured to shaft 28 and. has a plurality of peripheral groves 52 (FIGURE 3); A pair of screws 56 (FIGURE 9) and 58 respectively secure the free ends of a cord 60- to drum 50A The part of cord 60 secured by screw 56 passes through opening 64 in drum 50 to the uppermost groove 52 and then passes counterclockwise about drum 50 as viewed in. FIGURE 6 to a pulley mounted on. a support member 72 secured to an arm 74 pivotally mounted on plate 8 as indicated at: 76. This portion of the cord 60 then passes about pulley mounted on a support member 82 secured to plate- 8, and passes through an opening 83 in securing member 84 secured to a plate 88 and is held by a. screw Arm 74 is biased counterclockwise as viewed in FIGURE by an extension coil spring 90 which is secured to support member 72 by member 92 and secured to member .94 which in turn is secured to plate 8s The portion of cord 60 which is secured to drum. 50 by screw 58 passes out through opening 64 in drum 50 to the lowermost groove 52 and thence to pulley 96 mounted on support member 98 which is secured to arm 100 which in turn is pivotally mounted on plate 8 as indicated at 102,. This portion. of the cord then passes around pulley 104 mounted on support member 106 which is secured to plate 8 and then passes to securing member 84 to which it is attached as indicated above: Arm 100' is biased clockwise as viewed in FIGURE 6 by an extension coil spring 108 secured to arm 100 by a member 110 and. is secured to a member 112 which is in secured to plate 85 Arm 88 (FIGURE 8) has an upper plate 11.6 and a lower plate 118 spaced apart by a. rear spacer bar 120 and a front spacer bar 122 to which the upper and lower plates are secured as by screws Rollers .124 126, 128 and 130 lie between plates 116 and 118 and are journalled therein (FIGURE 6)" Plates 116 and .118 embrace a guide plate 132 having an. annulus 134 having an arcuate sur= face 136 which is engaged by rolers 124 and 126 and an arcuate surface 138 engaged by rollers 128 and 130. The surfaces 136 and 138 are concentric and the rollers 124, 126, 128 and 130 function to keep the center line of arm 88 perpendicular to surfaces 136 and. 138; Ball. hearings 140 in plates 116 and 118 engage plate .132.

Guide plate .132 is mounted on plate 8 by means of bolts 142, 142 (FIGURE 2) which pass through spacer members 144, 144 between guide plate 132 and bars 146, 146 and are secured by nuts 148, 148 as best seen in FIGURE 2. As best seen in FIGURE 3, bolts 150, 150 pass through guide plate 132, spacer members 152, 152, plate 8, bars 146, 146 and are secured by nuts 154, 154. As best seen in FIGURE 6, a buffer spring 158 is secured to guide plate 132 by one of the bolts 150 and a second butter spring 160 is secured to guide plate 132 by a second bolt 150, the butter spring 158 and 160 acting to engage arm 88 near the limit of its travel at either end to minimize dead time during reversal of motor 12 and to provide a torque aid while motor 12 is accelerating to running speed by unloading said motor.

A block 162 (FIGURE 8) is fixedly secured to spacer member 122 and is provided with a groove 164 for the reception of a base 166 of an ultrasonic transducer shown 'at 168. Pins 170, 170 engage grooves in block 162 to hold base 166 in the desired position. The optimum position of the ultrasonic transducer 168 is with the vertical center line of the outer face 172 passing through the cen ter of the are forming the surfaces 136 and 138 and indicated at C in FIGURE 4.

Referring now to FIGURE 7, there is diagrammatically shown a circuit for reversing the motor 12. There is provided a pair of power lines 180 and 182. Power line 182 by a line 184 is connected to a field winding 186 of motor 12.. Field winding 186 is connected to field winding 188. A line 190 containing a capacitor 192 is connected to line 184 and to switch contact 194 which is adapted to be contacted by switch arm 196 connected to actuating arm 198 of relay 200 which is connected to power line 180 and also connected to power line 182 by a line 201. Switch arm 196 is connected by a line 202 to a center tap indicated at 204 between field coils 186 and 188, A line 206 connects field coil 188 to line 208 which in turnv is connected to power line 180. Line 208 contains a capacitor 210 and is connected to a switch contact 212 which is adapted to be contacted by switch arm 196. A holding circuit for relay 200 comprises a line 214 connected to power 180 and to switch contact 216 which is adapted to be contacted by switch arm 218 connected to operating arm 198 of relay 200. A line 220 connects switch arm 218 to power line 180. A starting switch 222 is provided in line 180 along with normally closed switch 42 and normally open switch 36.

OPERATION Assuming the parts to be in the position shown in the drawings, starting switch 222 is closed causing field wind ings 186 and 188 to be energized with the relay 200 deenergized and switch arm 196 in contact with contact 194 to which line 190 is connected thus causing the motor to operate to rotate shaft 28 clockwise as viewed in FIGURE 6 which through cord 60 causes arm 88 to be pivoted clockwise about the point C shown in FIGURE 4, springs 90 and 108 acting to take up slack in cord 60 and rollers 124, 126, 128 and 130 moving in annulus .134 to control the pivoting about the point C by keeping the center line of arm 88 perpendicular to the arcuate surfaces 136 and 138.

When arm 88 reaches the position indicated at R in FIGURE 4, cam 30 has engaged roller 32 to close switch 36 which energizes relay 200 causing switch arm 196 to contact contact 212 to connect line 202 to line 208 and reverse the motor .12. Switch arm 218 is also brought into contact with contact 216. Thus when cam 30 by the reversal of motor 12 is carried away from roller 32 to permit switch 36 to reopen, the relay 200 remains energized being connected to line 180 through line .214, switch arm 218 and line 220. When arm 88 reaches the position indicated at 'L, in FIGURE 4, cam 30 has contacter roller 38 causing the movement of switch arm 40 to open switch 42 and thus de-energize relay Z causing switch arm 218 to move away from contact 216 and switch arm 196 to contact 194 causing motor 12 to reverse direction. The operation is then repeated causing arm 88 to oscillate as indicated in FIGURE 4 with the center line of the outer face of the arms ultrasonic transducer 158 being pivoted about the point C.

An alternative embodiment is shown in FIGURE 10. This embodiment is identical with the above described embodiment but has a modified driving means. Here a rod 232 is welded to upper plate 116 of arm 88 and passes freely through an opening 234 in a swivel 236 mounted on a nut 238 which is driven by a screw 240, A reversible motor 242 drives screw 240 which is mounted for rotation in bearing 244. Motor 242 can be controlled in the same manner as motor 12. As nut 238 travels back and forth, arm 88 will be moved about pivot point C Since ultrasonic scanning devices employing transducers are well known to the art as illustrated, for example by T. G. Brown Patent No. 3,086,390, issued Apr. 23, 1963, it is not deemed necessary in order to illustrate the invention, since they may be those conventionally used heretofore, to give any details herein with respect to the ultrasonic transmitting and receiving apparatus associated with the above described embodiments,

It will be understood that the above described embodiments of the invention are illustrative and are not in tended to be limiting.

What is claimed is:

1. A mechanism comprising means having a pair of opposed concentric Walls,

an arm including a pair of opposed plates embracing said means,

a plurality of rollers mounted between said plates and engaging said walls to maintain the center line of the arm substantially perpendicular to the walls,

the center of each of the arcs on which said walls lie being substantially at the outer end of said arm and means to oscillate the arm.

2. A mechanism comprising an arm,

means spaced inwardly from the outer end of the arm mounting the arm for pivotal movement about a point substantially at the outer end of the arm, said means including a pair of opposed concentric walls defining a sector of an annulus,

a plurality of rollers mounted on the arm and engaging the walls to maintain the center line of the arm sub stantially perpendicular to the walls; and

means to oscillate the arm.

3. A mechanism comprising an arm,

means spaced inwardly from the outer end of the arm mounting the arm for pivotal movement about a point substantially at the outer end of the arm; and

means to oscillate the arm, comprising a cord wound on a drum and having oppositely extending reaches secured to the arm and reversible motor means connected to the drum,

4. A mechanism comprising an arm,

means spaced inwardly from the outer end of the arm mounting the arm for pivotal movement about a point substantially at the outer end of the arm, said means including a pair of opposed concentric walls defining a sector of an annulus,

a. plurality of rollers mounted on the arm and engaging the walls to maintain the center line of the arm substantially perpendicular to the walls; and

means to oscillate the arm, comprising a cord wound on a drum and having oppositely extending reaches secured to the arm and reversible motor means con-- nected to the drum.

5. A mechanism comprising an arm having an inner and an unsupported outer end,

an ultrasonic transducer mounted adjacent the outer end of the arm,

means connected to the arm at a location spaced :in- 'wardly from the outer end of the arm and from the 5 transducer and mounting the arm for pivotal movement about. an unsupported point substantially coin.- cident with the outer face of the transducer; and means to oscillate the arm with respect to said mounting means;

6% A mechanism in accordance with claim 5 which. the mounting means has a. pair of opposed concentric walls and the arm is provided. with means engagin the said walls to maintain the center line of the army substan tially perpendicular to the walls:

7.. A mechanism in accordance with elaim 5 in which the mounting means has a pair of opposed concentric walls defining: a. sector of an annulus and the arm pro vided with means engaging the said walls to maintain the swivel means attached to the nut and having an open:-

ing slidably engaged by the rod a screw engaged by the :nut; and means to rotate the screw in two directions References (fitted UNlTED STATE-S PATENTS 2,828,635 4/1959 l ohnson et air, an M -89:22 2.940305 6/1060 illiams et. a1 73 B? FOREIG N PATENTS 630,4 5 l/ t96i Canada,

center line of the substantially perpendicular to 15 walls:

8 mecianism in accordance with claim 5 in which 5 to oscillate the arm comprises rod fixedly secure to the a 1 FRED C. MA'I'IE N JR Primary Examiner, 

